Wireless telegraphy.



' UNITED sTA s PATENT OFFICE.

GEORGE W. PIERCE, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO MASSACHUSETTS WIRELESS EQUIPMENT COMPANY, A CORPORATION OF NEW YORK.

WIRELESS TELEGRAPH.

No. emcee.

Specificetion of Letters Patent.

iatented Feb. Is, 1903.

Application and Hutch 15. 1906- Serlal No. 305.334.

citizen of the United Stat-es, residing: at (Janibridge, in the county of lvli'ildlcsox and the State of Massachusetts, have im cnted a. new and useful improvementin \sirelcss Telegraphy, of which the following is a full, clear, and exuci. de. .riplion, reference being had to the accompanying drawings, which form a part of 'lhis specii'ication.

The invention relates to wireless telegrziphy, and more particularly to the receiving siciion of a wireless telegraph system.

The object. of the invention is to provide apparatus at the receiving station of a. wireless telegraph system which may be readily tuned or brought into resonance wi t-h electromagnetic '{LYBS of widely varying length and by winch sharp resonance and intense signals or dull resonance may be secured under the various adjustments, and by which interference may be minimized.

The apparatus embodying the various features of the invent on is accordingly orovidcd with circuits 11nd connections by w rich the operator may secure either sharp or dull resonance. or may cause the currents produced by undesired s "nods to be divided into mo parts. lhc imcnsiry nnd phase of which only be so adjusted ihall'nctwo parts of the current will have tin.- suinc intensity and opposiie g' hnsc, thus ncutrelizing each other, while the divided currents caused by the desircd signals are imidc to have upproxinmtcly the mme phase, and thus add in intensity.

The various features of the invention will be understood from an inspection of the acconipanying drawings, and the following dct-ail description of the apparatus illustrated therein.

in the drawings Figure l is a diagram inutic ,i w ilill'\i1'2ii.l'i1 l' l-hc arrangement of circuiis whcn the proper connections are lll l lfi for ecuring sharp resonance, undcr normal conditions; Fig. .2 is a diagrannnut-ic view Zllusiraiing the :n'rangcnwnt of circuits when the proper onucctions are nnidc for dividing the currcnts into two parts when it is desired to cliniinnfc intcrl'crcnce duclo unusual condiiions; and Fig. I, is ndizigmmznnlic vicw showing an apparatus enihmlying the "ili'iulh l'cniurcs ol the invention, and showing thc connections by which the circuits of either Fig. l or Fig. 2, or a dolly resonant circuit, may be secured at the will 'of the 0 emit-or.

As in icated in Fig. 3 the were detocwr circuitand the antenna circuits are inductively coupled by a high-frequency transformer, the coils L, L of which are rorided with varied or adjusted. The secondary coil L is in circuit with e condenser U the capacity of which may be varied and is also in circuit with a Wave detector R which may be an electrolyt c receiver or some other form of wave detector. One end ofthe primary coil L is connected with the antenna A through an inductance coil L which is rorided with a sliding contact by which no number of active turns in the coil may be varied. The sliding contact of the primary coil L, is connected with one arm of a double switch S the other arm of which is connected with a pivot B of a switch 3. A condenser 0 the capacity of which may be varied, is connect,- ed with the conductor between the coils L L and with one of the right hand contacts for the anus of the switch S which contacts are electrically connected.

The arrangement of the circuits when the switch S is in engagement wit-h the right hand contacts is thatindicated in F ig. 1. The aritennncircuit is here connected through the switch S eitherwit-h the earth at G or with the wire H which may terminate in an artificial capacity to be used instead of the earth connection or may lead off horizontally for 1). suitable distance and then connect to a wire leading to some point on the antenna. Either of these connections is what 1 term a ground connection.

By varying the number of active turns in the coils L L these coils may be given the values which are besc suited to give sharp it is desired to tune the apparatus and by varying the number of active turns in the coil l1 and varying the capacity of the condenser if required, the stcpping up (or stepping down) between the coils- L, L and the periodicity of the detect-or circuit may be secured which are bestsuited to the inducing (late-flint R.

With the condenser U in shunt about the rcsonence and intensity of currents in the antenna. circuit with the wave lengtn to which of intense curl-cuts in the circuit of the wave sliding contacts by which t e number of active turns in the respective coils may be" primary coil L, and with the proper adiustl raphy an inductive connection, a detector ments of L L and U, the low-resistance-f closed circuit including C L is setinto per sistent OSCilllll'iOIl by the signals to which the i apparatus is tuned and is not aflected to a marked extent by signals of a ditl'erent t'requency. 'ith the proper adjustment 0i L and U these oscillations induce intense oscillotions 1n the circuit of the detector ll. Also by varying L L at. 10 several combinations E of adjustments each oi \shich ill give perslstent oscilhitlons 111 the closed circuit of (I and L. are possible and if one combination sutl'ers from interference another may be found that is free lrom interterence.

' hen itis desired to ehnnnnte or mnuuuzc rents in the priumry circuit as well as the currents inducedvin the secondary circuit pass through the wave detector. This arrzmgement of circuits is illustrated in Fig. 2 and with the connections thus made such values 5 may be given to the variable elements in the circuits that the currents produced by undcsired signals will have such phase relations and intensities that the primary and induced currents will neutralize each other while the currents Froduced by the desired signal will f have suci phase relations as to add oue'to the other thus increasing the intensity of the currents sent through tllv dclcctot' by such signal.

Since the sharp rcson-tnce secured by tho 1 arrangement. of cn'cuus ot Fig. 1' and llg. l v

may result in the operator failing to get de- Sired signals of which he does not know the periodicity in case his apparatus is slightly out of the proper adjustment l'orsuch signal a switch S is provided for opening the secondary circuit. \Yith this switch open and switch 8. in engagement with the contncts at the lcl't in Fig. it only currents set up in the antenna circuitwil puss through the wave detector. This will provide :1 circuit ol' couiparntivclr dull resonance to he used when Lheopcrntor is n'wni! iug sigunlsol' which he does not hnou the :ilt'l tlltll).

it will he understood (lull I do Hnl hunt myself to the use ollthe particular l'orm ol' circuits and romuw'linus slnm'u and dcserihed, and that the specific t'orm .md m

rangcment oi the parts may ltt \zllitd us found desirable.

l'luvingexplained lhc nature and \\l)J("l ol' the invention, and described one form of up m'utus in which the invention It!;l lucmodicd, \vhntl. chum is: i- ,1. in a receiving system tor wireless l(-lc and a condenser connected with the secondary, and connections for sending the current set up in the primary of the inductive connection through the detector.

2. in a receiving system for wireless telegmph)". an inductive connection having a. variable secondary. a detector and a condenser connected with the secondary, and connections for sending the currents set up in the priuuiry of the inductive connection through the detector.

3. ln :1 receiving system for wireless telegrnphy, an inductive connection having a V8. riahle secondary. :1 detector and a condenser (Uililkfllll'\\'llll the secondnsv. and connections for sending the currents setup intheprinmry of the inductive connect on through the deter-tor or directly to the ground. i

4. in a receiving system wireles telegraph an inductive connection having a. variable secondary, a detector and s1 variable condenser connected with the secondary. and connections for sending the currents set up in the primary of the inductive connection through the detector.

ln :1 ((tClYiflf" system forwvireless telegruph v. an inductive connection having a variable priuuiry and variable secondary. u detector and :1 condenser connected with the secondary, and connections for sending the currents set up in the prinmr of the. inductive connection through the detector.

H. in :1 receiving system for wireless telegraplrv. an inductive connection having a variable primer). :1 variable secondary, a detector and a condenser connected with the secornlzu'v, and connections for sending the currents set up in th primer of the inducti\c connection through the detector or directly to the ground.

T. in a receiving systeml'ur wireless telegrnphv, an inductive connection, a- Wave detector connected with the secondary of the inductive connection, and means for disconnccting the sccondzn'y and wave detector and sending the currents set up in the primary through the detector.

ln :1 receiving system for wireless telegruphy, an inductive connection with a variahlc primary. :1 wave detector connected with llu' -t('HHtlill' of the inductive connection and menus for disconnecting the secondary and now detector and sending the waves setup in the priin'zny through the detector.

ln witness hcrcol, l have hereunto set my lmnd. this 12th day of March. 1906.

GEORGE \Y. PIERCE.

lu the presence ol' li:.\ I.-. Visit, K. Dunno. 

